Sound recording and reproducing machine.



No. 655,557. Patented Aug. 7,1900. E. R. JOHNSON.

SOUND RECORDING .AND REPBODUCING MACHINE.

ion filed Aug. 23, 1898.)

(No Model.)

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SOUND RECORDING AND REPRODUCING MACHINE.

SPECIFICATION forming part of Letters Patent No. 5,557, dated August 7,1900.

Original application filed June 1, 1897, Serial No. 639,028. Divided andthis application filed August 23, 1898. Serial No.

' 689,291. (No model.)

To [LZZ whom it may concern.-

Be it known that I, ELnRIDen R. JOHNSON, a citizen of the United States,and a resident of the city of Philadelphia, State of Pennsyl- Vania,have invented certain new and useful Improvements in Sound Recording andReproducing Machines, of which the following is a'full, clear, and exactdescription, reference being had to the accompanying drawings, formingpart of this specification.

My invention relates to certain improvemen ts in sound recording andreproducing machines, and has for its object to simplify and improve theconstruction of what is commonly known as the sound-box and partspertaining thereto, my present application being a division ofapplication filed by me June 1, 1897, Serial No. 639,028.

In the accompanying drawings, Figure l is a perspective view of a soundrecording and reproducing device constructed in accordance with myinvention. Fig. 2 is a sectional view of Fig. 1. Fig. 3 is anexaggerated sectional diagram illustrating the diaphragm and the partsadjacent to its periphery.

Referring to the drawings, A represents the tubular section of thediaphragm-supporting frame connected at one end to a recesseddiaphragm-holding disk B and at its opposite end leading and connecteddirectly orindirectly to a mouthpiece, trumpet, or similarsoundconveying device. In the front face of the disk B is formed arecess b, having a step or flange c, on which is placed a ring d, ofsoft rubber or other suitable yielding material. In front of this ringthe diaphragm D is adjusted in position, and on the outer face of thediaphragm, hardly or slightly in contact therewith, is placed a secondsimilar ring 0?, which is confined in place by the disk E, secured byscrews e, as illustrated in Fig. 1, or by other suitable means to therecessed portion B.

It will be noted, as more clearly shown in Fig; 3, that. the peripheryof the diaphragm is out of contact with the inner peripheral walls ofthe recess, preferably to an extent of about four one hundredths of aninch. It is also clear, as particularlyillustrated in this figure, thatthe faces of the diaphragm near its periphery are practically out ofobstructive contact with the faces of the adjacent rubber rings, or thecontact, if any, is so slight as not-to prevent the diaphragm under theimpulses of the sound-Waves from vibrating practically evenly throughoutits entire area.

In a recess g, formed in the peripheries of the disks B and E, is fittedthe stylus-bar holder or spring-support H, having the springplateportion h formed of the desired thickness and adapted to be secured atone end to the bar I. The spring-support H comprises the plate portion71. and may have adapted thereto the fixed block-like portion h and theadjustable block it. The distance between the said blocks and thicknessand width of the plate govern the freedom of movement of the stylus-barI. The support H is secured to the disk B by any suitable means, such asthat illustrated in Fig. 1 or in Fig. 2. The enlargement of the orificein the plate portion 77?, through, which the screw g passes, willobviously permit of a slight lateral ad'- justment of the parts. In Fig.1 the orifice through which the screw g passes is preferably slightlyenlarged, which will permit of slight adjustment. In Fig. 3 the orificethrough whichthe screw 9' passes is shown as considerably enlarged topermit a more-extended adjustment.

Referring to Fig. 2, plate It is of considerable length and slotted atit for the passage of the securing-screw g. The plate It passes througha slot 77., formed in the center of the block h, which latter is alsoprovided with a slot 72. in line with the slot h for the passage of thesecuring-screw g; In adjustmentfor the lower or higher notes'therelative positions of the stylus-bar and diaphragm should not bealtered, and the plate h therefore'remains in the same position at alltimes, while the slotted block it is moved toward and from the block h,so as to decrease or increase the length of the plate between theadjacent edges of the blocks h h and then firmly secured in position tobind the plate, the effect when adj usted being substantially the sameas though "the block 71. were formed integral with such plate. It isclear that the plate 72?, having the elongated slot It", as shown inFig. 2, may, if desired, be also adjusted lengthwise in the block h toaccomplish the same purpose,

slightly-enlarged head i, which is connected to the diaphragm by aslightly-elastic cement i. In adjusting the stylus-bar to the diaphragmconsiderable care should be exercised.

At a suitable point in the length of the stylus-bar is a guard M,secured by screws m to the flange or plate in front of the diaphragm andhaving at its center a slot on, through which passes the stylus-bar I,the distance between the side and bottom walls of the slot and the sidesof the stylus-bar being preferably about one one-hundredth of an inch,so that lateral movement of the stylus-bar to any greater extent thanwhat is approximately the normal vibratory movement is prevented, andthus the bar is prevented from being torn from the diaphragm by anaccidental knock or jar. The vibration of the diaphragm beyond thenormal limits is prevented in one direction by the bottom wall of theslot m and in the opposite direction by the adjustable stop-screw n,screwing into the disk E at a point within the slot and immediatelyunder the stylus-bar.

I have discovered that to obtain the best results the diaphragm shouldmove substantially as a whole in both recording and reproducing and notbe rigidly confined at its peripheries in such a manner as to make itsimply a round spring in which the vibratory movement is greatest at thecenter or point of contact with the stylus.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. In a sound recording and reproducing machine, ayielding stylus-barsupport secured at one end to a fixed point and its opposite end to thestylus-bar, said support having an enlarged head at the point ofconnection with the stylus-bar, said yielding suph, provided verticallythrough said block to allow of lateral adjustment upon thesecuring-screw, substantially as described.

3. In a sound recording and reproducing machine, the combination of thediaphragmsupporting case, a diaphragm therein, a stylus-bar secured atone end to the center of r the diaphragm, a-slotted guard fitting oversaid stylus-bar, an adjustable set-screw pro j ecting from thediaphragm-case immediately under the stylus-bar, said set-screw andguard being adapted to limit the range of vibratory and lateral movementof said stylus-bar.

4. The combination of the diaphragm-support provided with a recess forthe reception of the diaphragm, a diaphragm of a diameter less than thediameter of the recess, a stylusbar having one end secured to the centerof said diaphragm, and a slotted guard fitting around said stylus-barand adapted to limit the range of movement of said stylus-bar.

5. In a sound recording and reproducing machine, the combination of thediaphragmsupporting case, a diaphragm therein,'disk, E, a stylus-barsecured at one end to the center of the diaphragm, and a slotted guard,M, secured upon the disk, E, having a central slot, m, adapted to thepassageof the stylusbar and to limit abnormal movement of thestylus-bar, substantially as described.

6. In a sound recording and reproducing machine, a yielding stylus-barsupport secured at one end to a fixed point and its opposite end to thestylus-bar, said support having an enlarged head at the point ofconnection with the stylus-bar, said yielding support being reduced inthickness throughout the remainder of its length to properly yield underthe impulses of the sound-waves to retain the diaphragm in its normalposition in the sound-box when at rest, substantially as described.

Inwitness whereof I have hereunto set my hand this 12th day of August,A. D. 1898.

ELDRIDGE R. JOHNSON.

Witnesses:

HORACE PETTIT, BENJ. F. PERKINS.

ICC

